Ministers have embarked on a concerted lobbying operation to prevent a backlash from the Trump administration to the under-16s social media ban announced by Keir Starmer on Monday.

Officials said they have spent weeks trying to reassure senior Trump officials and the US president himself that the restrictions were not specifically aimed at US technology companies.

The ban on platforms including X, Facebook, YouTube, Snapchat and TikTok, makes the UK the second country in the world to put sweeping limits on social media for children, after Australia did the same earlier this year.

But British officials are aware of the risk of retaliation from Trump, whom Starmer will meet at the G7 summit in Evian this week, and who has previously threatened the UK with “a big tariff” if the government does not drop its digital services tax.

One person involved in the effort said ministers had taken a three-pronged approach to “engage the companies, pre-brief the administration and myth bust in the media”. They added: “This is about protecting children in Britain, not taking on US tech.”

Asked about the possibility of sparking a fresh row with Washington, Starmer said on Monday: “I honestly think that across world leaders, there has always been a recognition that leaders have to take steps to protect children.”

He added: “In relation to President Trump, I spoke to him on Saturday, I’ll see him again this afternoon and, yes, of course, we’ll discuss this and many other issues, and lots of other leaders are very interested in it.”

By Monday evening the US president had not commented on the plans.

However his ally Elon Musk, who owns X, posted: “This censorship law is a wolf in sheep’s clothing. The real goal is to enable the UK government to track everyone.”

The plans involve a wider set of restrictions than have been applied in Australia. As well as setting age limits for many social media platforms, the government will prevent under-16s from live-streaming themselves, will ban adults from making unsolicited contact with children on gaming sites and will ban children under 18 from engaging with “romantic” chatbots.

Certain services have been specifically excluded, including YouTube Kids, Lego Play and Google Classroom.

Ministers are working on further limits to be unveiled next month, including late-night social media curfews for 16- and 17-year-olds.

Officials suggested on Monday that there could be additional regulations for virtual private networks (VPNs), which allow users to circumvent geographical internet controls.

Daniel Berntsson, the chief executive of Mullvad VPN, said he thought the government would probably require companies like his to demand users provide identification to prove their age.

The move could have a huge impact on the lives of young people. Nine out of 10 13- to 15-year-olds have a social media account and say that their main sources of news are YouTube, TikTok, Facebook and Instagram.

Starmer told a press conference in Downing Street: “Social media is making children unhappy, it’s making it easier for bullies to harass and abuse them, and it could even be harming their mental health.”

The prime minister once opposed such a move, but said he had been persuaded by the evidence that had been gathered during the government’s 12-week consultation.

He denied rushing his announcement in an attempt to cement his legacy should he be ousted as prime minister in the coming weeks.

Andy Burnham, the Greater Manchester mayor, is hoping to win the Makerfield byelection later this week and has promised to challenge the prime minister if he does so.

“This is a huge statement of our values, who we are as a country. And it’s a way of actually bringing our country together,” Starmer said.

The announcement was welcomed by the Conservatives – who called for a ban several months ago – Labour backbenchers and several campaign groups.

Esther Ghey, the mother of the murdered teenager Brianna Ghey, said she was happy about the ban, adding it could “save so many children’s lives”.

But it has encountered scepticism from some experts, including an independent expert panel convened by the government, which found the impact of social media is “nuanced” and did bring some benefits to teenagers.

The world’s largest technology companies have warned that the move would push teenagers towards more dangerous parts of the internet, but are not thought to be preparing legal action to block it.

A spokesperson for Meta, which owns Facebook and Instagram, said: “As we’ve seen in Australia, bans risk isolating teens from online communities and information, and driving them to unregulated alternatives that lack built-in protections and parental controls.”

YouTube said: “Blanket bans push kids out of such curated, supervised, beneficial experiences and towards anonymous, less-safe services.”

Ministers have asked the media regulator, Ofcom, to come up with detailed proposals for how to enforce the ban.

Companies could be asked to take into account written forms of identification, the number of years spent on a platform and facial recognition tools when deciding whether people should be allowed to use their services.

Ofcom will make its recommendations in the autumn, while the technology secretary, Liz Kendall, said on Monday she wanted to see a ban in place “as early as possible … first couple of months of 2027”.